The present invention pertains to a granulated riboflavin product. Riboflavin in pure form exists as a clingy, dusty, highly electrostatic powder which sticks to and fouls processing equipment, and furthermore tends to bridge and clump during handling. These handling and processing problems have been overcome in the product of the present invention. The high flowability, of the product of the present invention can virtually eliminate product losses due to a buildup of riboflavin powder on processing equipment. Eliminating buildup of powder (i.e., fines) on the equipment also eliminates the labor which must be expended to remove the material from the equipment surfaces.
The granulated riboflavin product of the present invention has a heretofore unachieved combination of high vitamin B content (i.e., vitamin B content of at least 75 weight percent based on total product weight) together with high flowability (i.e., a flodex flowability index of at least 75).
The closest art known to the Inventors includes the following patents: U.S. Pat. No. 4,868,180; U.S. Pat. No. 3,962,384; U.S. Pat. No. 4,486,435; and European patent application 0,219,276. Although this art is the closest art of which the Inventors are aware, none of this art describes a product having the combined characteristics of: (1) high riboflavin content of the product of the present invention, together with (2) the high flowability of the product of the present invention. Furthermore, none of this art provides any quantified measurements which provide quantitative characterization of the level of flowability present in the products disclosed. Furthermore, only one of these patents (i.e., U.S. Pat. No. 4,868,180) refers to a "high" riboflavin product. As is shown by comparative examples herein, a product produced in accord with the method described in the '180 patent has a much lower flowability than that found in the product of the present invention. The product produced in the '180 patent is low in flowability because (1) the '180 patent describes a conventional fluid bed process, and (2) the '180 patent describes a process which requires pulverizing the agglomerated product in a Fitz mill using a punched screen. It has been found that the use of a Fitz mill results in the partial deagglomeration of the granules and hence the freeing up of individual crystals. It has been found that the fluid bed agglomeration process as described in the '180 patent fails to agglomerate at least 50 weight percent of the individual riboflavin crystals. Thus the product produced in the '180 patent comprises at least 50 weight percent pure riboflavin (i.e., riboflavin unassociated with any binder) due to both: (1) failure to granulate at least 50 weight percent of the vitamin in the fluid bed granulation step, as well as (2) the freeing up of individual riboflavin crystals in the milling step. Most importantly, however, it has been found that the product produced by the process described in the '180 patent has a flowability significantly lower than the flowability of the product of the present invention (see comparative Examples 7 and 8, infra).
None of the other art referred to above describes products which are "high" (i.e., greater than 75 weight percent) in riboflavin. Products having large amounts of binders (i.e., binder in an amount greater than 25 weight percent) permit the manufacture of products higher in flowability because the higher amount of binder provides a greater binding effect which in turn agglomerates more of the individual riboflavin crystals. Thus it is very difficult to make a product comprising 90 to 99 weight percent riboflavin with from 1 to 10 weight percent binder, because the relative proportion of binder is so small that it is very difficult to tie up (i.e., agglomerate) the individual crystals present. However, the product of the present invention comprises essentially no pure riboflavin. The Inventors of the product of the present invention have unexpectedly found that it is possible to agglomerate essentially all of the riboflavin in a product which has a surprisingly small amount of binder therein.